Process of producing caffein-free coffee



Patented May 1, 1934 UNITED STATES PROCESS OF PRODUCING CAFFEIN-FREE COFFEE Erich Scheele, Osterdeich, Bremen, Germany v No Drawing. Application July 6, 1932, Serial No.

621,125. In Germany Claims.

Hitherto the caflein has usually been removed from coffee by subjecting green coffee beans to a preliminary treatment with water or aqueous liquids at raised temperature and thereupon ex- 5 tracting with caffein-dissolving agents, such as for instance benzine, benzol, trichlorine-ethylene or the.like, whereupon the extraction agent is drawn off and the beans during an after treatment are completely freed from rests of the extraction agent. The arrangements used for moistening the coffee with steam, water or aqueous liquid are rather expensive, particularly the rotating extracting devices, which also suffer from the drawback, that they frequently turn leaky.

It has also been proposed to extract the green coffee beans in centrifuge by means of suitable solvents.

Finally it is known to-treat the coffee beans with an ammonia-containing aqueous fluid and subsequently with a solvent adapted to take up .the alkaloid from the ammonia-containing fluid.

The ammonia releases the caflein from the cofiee beans and the result of this is, that the cafiein readily passes over into the surrounding fluid. From this fluid the cafiein is thereupon removed by the solvent.

All known processes require the before mentioned preliminary treatment with steam or water at raised temperature. The extraction of the caffein can only be performed subsequently to the preliminary treatment and the older processes thus involve two separate stages of operation.

The object of the presentinvention is to provide' for a simple treatment of. coffee beans to remove the cafiein substantially completely in a single stage of operation.

According to the invention the solvent for the caffein is caused to act upon the coifee beans in emulsified state. The treatment may be carried 40 out with a previously prepared emulsion, but it is also possible to produce the emulsion during the treatment. Suitably the solvent is emulsified with water when it is in contact with the coffee July '1, 1931 traction devices hitherto used. The rotating extractors are of low efliciency and work in the whole very ineconomically, but it was hitherto not possible to dispense with the use of same at the extraction of cofiee beans, since the moistening or wetting stage of the process could not be carried out in extractors of simpler design.

According to the present inventionan emulsion of an organic cafiein-solvent and water is caused to act directly on the coffee beans. The emulsion I is suitably produced and maintained by moving both fluids continuously during the extraction. The emulsion may for instance be produced by calling forth a continuous intermixing or interwallowing movement of the fluids (solvent and water). A very effective manner of intermixing the fluids consists for instance in sucking off the fluids at the top and the bottom of the apparatus, reintroducing same and passing the emulsion through the cofiee beans. By this treatment-a thorough penetration of the coffee beans is secured and the cafiein is completely extracted.

Ewample 1000 kg. of air-dried coffee-beans are fllled into a vertically arranged preferably cylindrical extraction vessel, whereupon the solvent (for instance trichlorine-ethylene, chloroform, benzol or the like) is added. Thereupon 400 kg. of water are added andthe vessel is closed. The contents of the vessel is heated and both fluids, i. e. solvent and water, are caused to circulate and wallow rapidly in order to form the emulsion. The. fluids may for instance be intermixed by' means of a propeller or another stirring device or by means of a pump of sufficient capacity: If a pump is used the fluids may for instance be sucked 01f at great velocity from the bottom of the container and be reintroduced into the same at the upper level of the charge. This circulating movement may of course also be reversed. The verticaLflow caused by this circulation will efiect a thorough intermixing of the substances in the vessel and the emulsion is rapidly formed. The specific beans and is acting upon the same. By carrying 45 out the process in this manner the special moistening stage is avoided, since the solvent for the caflein and the water act upon the cofiee beans simultaneously. When working in this manner also the extraction process is advantageously in- 5Q fluenced, because the solvent will penetrate the cells of the cofiee beans together with the water.

A further advantage of the novel process resides in the fact that common stationary extractors may be used for the lixiviation of the 55 caffein instead. of the very expensive rotating exweight of the solvent used is without importance. The extraction may therefore if desired be car'- ried out-with solvents which are heavier than water or with solvents which are lighter than water.

When the fluids have been intermixed for about V 30 minutes the coifee beans will 'have absorbed the water completely. The extraction, may now be continued in the usual manner. After the extraction has been completed the. coffee beans are heated in order to remove the last remains of the solvent from the same. 'I'he'caifein may be sep- 11o and heating the mixture during the treatment.

3. A process of producing caffein-free cofiee, comprising the steps of acting upon coffee beans with water and a caffein-solvent and emulsifying the said solvent during the treatment.

4. A process ofproducing caflein-i'ree coffee,

comprising the steps of acting upon coffee beans with water and a cafiein-solvent and'intermixing the water and the solvent continuously and circulating same through the body of coffee-beans, in order to emulsify the solvent.

5. A process of producing cafiein-free cofiee, comprising the steps of introducing coffee beans, an organic solvent and water into a vessel, closing and heating the vessel, forming an emulsion of the solvent and the water, allowing this emulsion to act upon the coffee beans for a predetermined period and maintaining the solvent and water in emulsified state during the treatment.

ERICH SCHEELE. 

